hobart



(No Model.) 2 sneetssheet 1. J. C. HOBART. VALVE EUR GOMPOUND STEAMENGINES.

No. 11671933 Patented Feb. 2, 1892.

(No Model.) l 2 Sheets-Sheet 2,

J. C. HOBART.

VALVE EOE GOMPOUND STEAM ENGINES.

No. 467,933. Patented Feb.. 2, 1892.

Eg/.3. H94.

' IA 'IIIIIIII Mn/'@6565 Invader UNITED STATES PATENT OEEICE.

JAMES C. IIOBART, OF CINCINNATI, OHIO, ASSIGNOR TO THE TRIUMPH COMPOUNDENGINE COMPANY, OF SAME PLACE.

VALVE FOR COMPOUND STEAM-ENGINES.

SPECIFICATION forming part of Letters Patent N o. 467,933, datedFebruary 2, 1892.

Application filed August 31, 1891. Serial No. 404,285. (No model) To allwhom, it may concern:

Be it known that I, JAMES C. HOEART, a citizen of the United States,residing at Cincinnati, in the county of Hamilton and State of Ohio,have invented new and useful .Improvements in Distribution-Valves forCompound Steam-Engines, of which thefollowing is a specification.

My invention relates to compound engines,

its object being to produce a simple, economical, and effectivedistribution-valve and valve-chest for effecting the induction,expansion over, and final exhaust of steam in a direct manner withconservation of heat, and in form to insure by due proportion andrelation of parts a proper degree of economical efficiency in theworking of the engine.

To this end it consists in a cylindrical valvecasing having a singleinlet-port with a single distribution-port for eachhigh-pressurecylinder symmetrically disposed at opposite sides thereof(longitudinally) and a single exhaust-port with a singledistribution-port for each low-pressure cylinder symmetrically disposedat opposite sides thereof, (longitudinally,) and, further, in a hollowpiston-valve constructed in detail as hereinafter set forth, wherein thetubular interior of the valve is wholly employed as a passage for theexpansion over of the steam, the admission being controlled by aperipheral groove surrounding the valve near one end and the exhaust bya similar groove at the other end. The valve is especially adapted tothe use of twocylinder engines, whether single or double acting, or toany engines wherein the initial steam is expanded upon the return strokeof the high-pressure pistons against low-pressure pistons coupled to anoppositely set crank. It is particularly adapted to the type of suchengines having one or more differential cylinders withl correspondingpistons used, respectively,\vith high and low pressure steam.

Mechanism embodying my invention is illustrated in the accompanyingdrawings,in which* Figure l is a general side or front elevation of avertical two-cylinder engine of the differential-cylinder type to whichmy invention is applied; Fig. 2, a horizontal section through the upperreceiving-port and valvechest; Fig. 3, a vertical cross-section of theengine, taken through the axial plane of the valve and valve chest; andFig. 4, an enlarged vertical section of the valve and chest, taken in anaxial plane parallel with the common axial plane of the workingcylinders.

Referring now to the drawings, A A and B B designate the cylinders,respectively, of a vertical two cylinder engine, and C the crank -caseconstituting a support for the same. The cylinders open into thecrankcase and are fitted in their lower and larger ends A B with pistonsD E of the bucketplunger type extended by cylindrical plungers D E,respectively, into the smaller ends A B of the cylinders, the initialsteam being introduced in each smaller cylinder against the end of theplunger-piston extension as a high-pressure piston, and thence expandedover to the opposite larger cylinder against the annular upper surfaceof the bucket-plunger piston therein. There are thus constituted, ineffect, four cylinders, two high-pressure and two low-pressure, havingtheir pistons operated in the same direction butatopposite times byconnection with oppositely-set cranks upon the crank-shaft S. These andother constructive details being common in this class of engines I neednot describe further.

The valve-chest is a third cylinder F, which, for constructive reasons,I prefer to place parallel to and between the Working cylinders and alittle rearward of their common axial plane. Also, for constructivereasons,I have shown it herein of full length to secure symmetrical andequal distribution ports and passages to all the cylinders, but thevalve may be made shorter and the cylinder-passages lengthenedaccordingly.

Into the valve-casin g near the top enter two induction-ports d' b',symmetrically disposed at opposite sides, respectively, of a live-steamreceiving-port s. The ports a ZJ connect, respectively, by passages c2b2 with the upper ends of the smaller working cylinders A B and servefor the admission of live steam to the working cylinders and also forits subsequent expansion over through the valve, as will be explainedlater.

Near the bottom of the valve-casing are two ports c d', symmetricallydisposed at opposite sides, respectively, of an exhaust-port :n andconnecting to the upper ends of the larger cylinders A B by passagesc2612, these serving for the admission of the expansionsteam from andthrough the valve into the larger cylinders and its linal exhausttherefrom around the valve, as will be explained later.Y The passagesconnecting the several distribution-ports to the respective cylindersare thus provided of equal length so as to"ob-` tain equal clearance inthe successive distributions to the cylinders.

The valve G is 'a tubular piston closed at both ends, hollow interiorly,and provided with openings or ports, as follows: Near the to'p are ports'e f, communicating with the interio-r passage p, extending the entirelength ofthe valve `loetween its end-closing heads. The ports e fare atopposite sides of a -peripher-al .groove g, which is constantly'incommunication with the live-steam receiving-port s of the casing anddistributes the live 'steam alternately at opposite reciproca-tions ofthe valve to the lcylinder ports and passages a a2 b b2. The ports c falternately register with the same ports a boppositely with thesteamgroove fs, and permit the expansion-'steam to pass into theinterior passage y) of the valve. Near the bottom of the valve are twofarther ports 'h i, opening to the interior passage p at opp'ositesidesvof an annular .groove j. rlhe ports lh t' register alternately with theports and :passages c c2 d i12-and permit `the expansion-'steam to flowthrough and lfrom the interior passage@ of the valve into the largercylinders A B. Thefg-roove j also registers with the ports yc c2 inopposite alterna-tions with the valve-ports -h a', thus permitting thefin-'a1 exhaust to pass outward. The lower end of the valve-casing beingopen, a connectingrod fr, pivot-ed to the lower end of the valve G,'connectsV it through said opening and a similar one in thecrank-case tothe eccentricyoke t, as indicated in Figs. l and 3. The ports, both ofthe valve-chest and the valve, are preferably extended entirely aroundthe same and are bridged 'across parallel with the valve-axis bysuitable bridges, as shown. Packing-rings o are provided upon th-e valvein suit-able grooves at each side of Aeach port, except between the twocentral expansionports f h, where they are not needed.

The operation of the valve has been to a lgreat exten-t indicated in theforegoing description, but may be summarized as follows: The valvebeingat its highest positio-n,steam is'deli-vered to working cylinder A,moving-its pistons -dow-n. A-At the same time the live steam, which hasjust 4completed its work -in working cylinder B, now expands overthrough passages and ports U2 b through the interior valve-passage p andports and passages c c2 to working cylinder B. So in a similar mannerthe induction, expansion, and exhaust takes place between the cylindersin opposite sequence in Iaccordance with the reversed movement of theparts. The valve, it will be observed, is balanced in respect to steampressure and exhaust, and the expansion-passage is practically neutralin respect to gain or loss of heat from high-pressure or exhaust steamand is devoted exclusively to the expansion-steam. The area of saidexpansionpassage may of course be reduced as much as desired. The valveis preferably made in one piece, as shown. It may, however, be made intwo pieces-the shell from the dotted line Fig. tpupward, including theend piston, in AoneY piece, and similarly from the dotted line 'ydownward in another--connected by a central rod sec-ured in the endpistons.

I claim as my invention and desire to lsecure by Letters Patent of theUnited States l. In a compound engine of two low-.pressure and twohigh-pressure cylinders operating oppositely-set cranks, a cylindricalvalvecasing having a single steam-inlet port and symmetrically disposedin-relation thereto and at opposite sides thereof longitudinally asingledistribution-port for each high-pressure cylinder, a singleexhaust-port, and symmetrically disposed in relation thereto and at0pposite sides thereof longitudinally a single distribution-port foreachlow-pressure cylinder, in combination with a 4reciprocating-piston valvegoverning the steam-distribution through said ports, substantially asset forth.

2. In a compound 'engine of the character described, in combination witha cylindrical valve-easing having single inlet and outlet ports andsingle distribution ports for the high and low pressure cylindersarranged symmetrically at opposite sides longitudinally of the inlet andoutlet ports, respectively, a reciprocating-piston valve having twoperipheral grooves, one near each end, respectively, Y

constituting cavities exclusively for `the delivery of steam to thehigh-pressure cylinders and the iinal exhaust of steam from thelowpress-ure cylinders, an internal passage exclusively for theexpansive distribution in common of steam between each high and itsproper low pressure cylinder, and ports opening from said internalpassage through the shell of the valve beyond and between saidperipheral grooves, substantially as set forth.

3. In a compound steam-engine, in combination with two or moreindependent singleacting wor-king cylinders for vhigh and low pressuresteam, a single cylindrical valvechest common to all the cylindershaving single independent ports and passages symmetrically arrangedconnecting the casing with the cylinders, respectively, and a singlereciprocating distribution-valve `having a tubular XOO IIO

body, a pair of end pistons, ports between the expansion over of steamfrom the high to said pistons communicating with and conthe loW pressurepistons in common, substanneoted by a passage Within the valve, andtially as set forth. two annular grooves or ports in the shell of Intestimony whereof I have hereunto set 5 the Valve, one governing theentire distribumy hand in the presence of two subscribing I5 tion oflive steam to the l1igh-pressure oylin- Witnesses. ders and balancingvthe valve, the other the JAMES C. HOBART. final exhaust of steam fromthe low-pressure lVitnesses: cylinders, and Idie interior passage of theR. M. HOSEA, Io valve and its Communicating ports governing E. llOSEA.

